The subject has been pencilled in for a general debate at the full Commission meeting next Wednesday (30 July) in a bid to clear the air between the Commissioners most closely concerned before the summer break.

Despite repeated attempts to find common ground over the last six months, Competition Commissioner Karel van Miert and Transport Commissioner Neil Kinnock appear as divided as ever over the issue.

Next week’s debate is aimed at allowing other Commissioners to intervene and, hopefully, pave the way for progress in the autumn.

Kinnock’s officials sparked the long-running battle by recommending that the Commission should publicly recognise the unofficial practice of big airlines buying and selling slots at twice yearly international meetings and bring it within the EU’s current code of conduct governing slot allocation.

But Van Miert argues that slots are not owned by anyone and should be regarded as a public resource which cannot be bought and sold for profit. Within the airline industry there are also fears that carriers with the biggest bank balances will be able to buy the slots.

Kinnock’s officials have tried to dispel Van Miert’s concerns with a guarantee that he would be free to order firms to hand over slots when scrutinising airline alliances such as that between British Airways and American Airlines. But so far, the Competition Commissioner has refused to budge.

On other isues, the two sides have made some progress in bridging their differences. These include the definition of new entrant airlines – firms keen to start services from airports where they are hampered by the scarcity of slots – and measures to free up slots for their use.

A report drawn up for the Directorate-General for transport (DGVII) last year suggested the definition of new entrant airlines could be rewritten to specify airlines with no slots at all at an airport instead of including those with a handful of slots. More controversially, it also suggested banning small aircraft from using slots at overcrowded airports.

But Andrew Clarke, assistant director of air transport policy at the European Regional Airlines Association, said that officials appeared be moving towards a “more generous” definition of new entrants.

One idea being considered would allow airlines to be classified as new entrants if they were offering a service for the first time on a particular route, as long as they did not hold more than a given percentage of all slots at the airport.